BS Zoology Semester Exam MCQs

Hemoglobin binding is crucial for oxygen transport. Impaired binding reduces oxygen delivery, causing tissue hypoxia.

Hemoglobin binds oxygen reversibly in red blood cells, allowing blood to carry far more oxygen than plasma alone.

Invertebrate clotting responses help seal wounds and trap pathogens. This is part of innate defense and fluid balance.

Arteriole constriction reduces local perfusion. Less warm blood reaches the tissue, making it cooler and paler.

Dehydration lowers plasma volume, which can reduce venous return and blood pressure. Circulatory regulation attempts to compensate.

Hemocyanin is a copper-containing respiratory pigment found in many arthropods and molluscs. Oxygenated hemocyanin is often bluish.

Lymph nodes filter lymph and contain immune cells. Swelling often reflects immune activation during infection.

Large capillary surface area and short diffusion distance maximize exchange of gases, nutrients, and wastes between blood and cells.

Lacteals are lymphatic vessels in intestinal villi that absorb dietary fats and transport them as chyle into lymphatic circulation.

Closed systems maintain blood within vessels, allowing higher pressure and more precise distribution to active tissues. This supports greater activity in many animals.

Lymph is derived from interstitial fluid and usually contains fewer proteins and lacks red blood cells. It contains lymphocytes and other immune components.

Without circulation, internal transport depends on diffusion, which becomes inefficient over long distances. This limits body size and activity.